Do bicarbonate-based solutions for continuous renal replacement therapy offer better control of metabolic acidosis than lactate-containing fluids?

INTRODUCTION

Evidence that bicarbonate haemofiltration and dialysate fluids are superior to lactate in patients with acute kidney injury treated by continuous renal replacement therapy (CRRT) remains controversial.

METHODS

We prospectively audited acid-base during the first 48 h of CRRT in 62 patients, using bicarbonate and lactate fluids.

RESULTS

Baseline lactate was greater in the bicarbonate group (4.76 ± 0.77 vs. 2.92 ± 0.5 mmol/l, p < 0.01), but pH, bicarbonate, chloride and base excess were similar. Lactate fell significantly in the bicarbonate group to 2.88 ± 0.3 mmol/l at 24 h and 2.39 ± 0.2 mmol/l at 48 h, but not in the lactate group. Base excess improved more with bicarbonate, median increase in the first 24 h was 51.6% (29.1-96.9) versus 18.5% (-5 to 55) with lactate and 74.2% (38.5-123) versus 36.1% (-3.6 to 68), p < 0.05 at 48 h. However, there were no significant differences in bicarbonate, chloride, pH, blood pressure and vasopressor requirements. 13.3% of patients were switched from lactate to bicarbonate fluids due to failure to correct acidosis. Subgroup analysis of 19 patients with liver failure showed similar results.

CONCLUSION

Bicarbonate fluids led to a more rapid fall in lactate and greater improvement in base excess during CRRT, but not overall control of acidosis.

A prospective assessment of renal impairment after preparation for colonoscopy: oral sodium phosphate appears to be safe in well-hydrated subjects with normal renal status

BACKGROUND

The outcome of colonoscopy is highly dependent upon the quality of bowel cleansing prior to the procedure. Oral sodium phosphate solutions (OSPS) or preparations containing polyethylene glycol (PEG) are generally employed. However, the safety of administering OSPS prior to colonoscopy has been questioned because of the potential for renal failure.

AIM

To compare rates of renal failure after OSPS and PEG in a randomized, prospective trial and to assess the quality of colonoscopy after these two bowel preparations.

METHODS

Subjects with eGFR >or= 60 ml/min/1.73 m(2) and expressed willingness to adhere to hydration recommendations were randomized to OSPS or PEG solutions. Renal function was assessed 1 week prior to, immediately prior to, and 1 week after colonoscopy.

RESULTS

No subject had acute kidney failure after OSPS or PEG. OSPS was associated with significant increases in the serum phosphate and sodium levels and significant decreases in the calcium and potassium levels. These values returned to normal limits in all subjects by 1 week after colonoscopy. The quality of colonic cleansing was superior after OSPS than after PEG (Ottawa score 2.5 +/- 2.2 vs. 3.5 +/- 2.3, respectively, P < 0.05). The detection of one or more adenomatous polyps was higher after OSPS than after PEG.

CONCLUSIONS

Renal failure was not detected after the use of OSPS for colonoscopy preparation in subjects with recently documented normal renal function who were able to consume the required amounts of water after each dose. However, based on the number of subjects studied, the theoretical risk of this complication is still between 0 and 6.3%. Thus, it is appreciated that only a very large prospective trial would have yielded a more accurate estimate of the likelihood of renal compromise after OSPS. Despite this caveat, OSPS has advantages over PEG in terms of the adequacy of colonic visualization and the number of polyps detected.

Magnetic Drug Targeting in the Permeable Blood Vessel—The Effect of Blood Rheology

The present investigation deals with finding the trajectories of the drug dosed magnetic carrier particle in a microvessel, which is subjected to the external magnetic field. We consider the physical model that was given in the work of Furlani and Furlani (2007, “A Model for Predicting Magnetic Targeting of Multifunctional Particles in the Microvasculature,” J. Magn. Magn. Mater., 312, pp. 187–193), but deviating by taking the non-Newtonian fluid model for the blood in the permeable microvessel. Both the Herschel–Bulkley fluid and Casson models are considered to analyze the present problem. The expression for the fluid velocity in the permeable microvessel is obtained using the analogy given by Decuzzi et al. (2006, “The Effective Dispersion of Nanovectors Within the Tumor Microvasculature,” Ann. Biomed. Eng., 34, pp. 633–641) first. Then the expression for the fluidic force for the carrier particle traversing in the non-Newtonian fluid is obtained. Several factors that influence the magnetic targeting of the carrier particles in the microvasculature, such as the permeability of the inner wall, size of the carrier particle, the volume fraction of embedded nanoparticles, and the diameter of the microvessel are considered in the present problem. The trajectories of the carrier particles are found in both invasive and noninvasive targeting systems. A comparison is made between the trajectories in these cases in both the Casson and Herschel–Bulkley fluid models. The present results for the permeable microvessel are compared with the impermeable inner wall trajectories given by Shaw et al. (2010, “Effect of Non-Newtonian Characteristics of Blood on Magnetic Targeting in the Impermeable Micro Vessel,” J. Magn. Magn. Mater., 322, pp. 1037–1043). Also, a prediction of the capture of therapeutic magnetic nanoparticle in the human permeable microvasculature is made for different radii and volume fractions in both the invasive and noninvasive cases.

Epoxyeicosatrienoic acid analogs and vascular function

Arachidonic acid metabolites, eicosanoids, are key contributors to vascular function and improper eicosanoid regulation contributes to the progression of cardiovascular diseases. Epoxyeicosatrienoic acids (EETs) are synthesized from arachidonic acid by epoxygenase enzymes to four regioisomers, 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET. These EETs have interesting beneficial effects like vasodilation, anti-inflammation, and anti-platelet aggregation that could combat cardiovascular diseases. There is mounting evidence that each regioisomeric EET may have unique vascular effects and that the contribution of individual EETs to vascular function differs from organ to organ. Over the past decade EET analogs and antagonists have been synthesized to determine EET structure function relationships and define the contribution of each regioisomeric EET. A number of studies have demonstrated that EET analogs induce vasodilation, lower blood pressure and decrease inflammation. EET antagonists have also been used to demonstrate that endogenous EETs contribute importantly to cardiovascular function. This review will discuss EET synthesis, regulation and physiological roles in the cardiovascular system. Next we will focus on the development of EET analogs and what has been learned about their contribution to vascular function. Finally, the development of EET antagonists and how these have been utilized to determine the cardiovascular actions of endogenous epoxides will be discussed. Overall, this review will highlight the important knowledge garnered by the development of EET analogs and their possible value in the treatment of cardiovascular diseases.

Clinical trial: the efficacy and safety of routine bowel cleansing agents for elective colonoscopy in persons with spinal cord injury - a randomized prospective single-blind study

BACKGROUND

As difficulty with evacuation is a common occurrence in individuals with spinal cord injury, preparation prior to colonoscopy may be suboptimal and, perhaps, more hazardous.

AIM

To assess the safety and efficacy of bowel cleansing regimens in persons with spinal cord injury.

METHODS

Randomized, prospective, single blind study comparing polyethylene glycol (PEG), oral sodium phosphosoda (OSPS) and combination of both for colonic preparation prior to colonoscopy in subjects with spinal cord injury.

RESULTS

Thirty six subjects with eGFR > or =60 mL/min/1.73 m(2) were randomized to PEG or OSPS or PEG+OSPS. Regardless of bowel preparation employed, >73% of subjects had unacceptable colonic cleansing. No subject in the OSPS preparation group demonstrated a decrease in eGFR or an increase in serum creatinine concentration from the baseline. OSPS and PEG+OSPS preparations caused a transient change in serum potassium, phosphate and calcium concentrations, but no change in electrolytes was noted in the PEG group.

CONCLUSIONS

Neither OSPS alone, PEG alone nor their combination was sufficient to prepare adequately the bowel for colonoscopy in most patients with spinal cord injury. However, administration of OSPS and/or PEG appears to be safe in the spinal cord injury population, provided adequate hydration is provided.

Enhanced Blood Pressure Response to Mineralocorticoid Stimulation in Normotensive Members of Hypertensive Families

Currently normotensive offspring of essential hypertensive parents often have disturbances in blood pressure (BP) regulation such as abnormalities in electrolyte homoeostasis, increased salt-sensitivity and/or impaired renal Na(+)-excretion. Whether an altered reactivity to mineralocorticoids may also play a role is presently unknown. Therefore, we investigated BP (recorded during 24 h), plasma atrial natriuretic factor (ANF), cyclic guanosine monophosphate (cGMP), aldosterone (PA) and renin activity (PRA), 24-h urine electrolyte and cGMP excretions measured on 4 consecutive days, as well as other variables, after 1 week on placebo and after 3 weeks of 9 alpha-fludrocortisone-acetate (9 alpha F) administration, 0.6 mg/d in 12 normotensive sons of essential hypertensive parents (SEH) and 12 body-mass-index- and age-matched (25 +/- 1[+/-SEM]yr) sons of normotensive parents (SN). On placebo, the 2 groups did not differ significantly in average 24 h BP (mean BP 95 +/- 2 vs 95 +/- 2 mmHg), plasma-ANF (40 +/- 7 vs 30 +5 pg/ml), cGMP (6 +/- 0.4 vs 6 +/- 0.5 nmol/l), PRA (1.3 +/- 0.1 vs 1.6 +/- 0.2 ng/ml/h), PA (9 +/- 0.5 vs 10 +/- 0.9 ng/dl), hematocrit (44 +/- 0.7 vs 44 +/- 0.4%) and 96-h urinary-Na+ (mean 205 +/- 13 vs 195 +/- 16 mmol/d), -K+ (69 +/- 6 vs 78 +/- 7 mmol/d) or -cGMP (461 +/- 35 vs 483 +/- 32 nmol/d). 9 alpha F significantly increased BP in SEH (p < 0.005) but not SN (107 +/- 2 vs 100 +/- 2 mmHg, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Immunomagnetic purification of T cell subpopulations

This unit describes a general method for physical separation of cell subpopulations from a heterogeneous mixture of cell types. The technique relies on having an appropriate monoclonal antibody or mix of monoclonal antibodies that distinguish between the cell types being separated. Its advantages over other antibody-mediated selection techniques are purity of resulting cell preparation, reproducibility of separation, and ease of handling small to large numbers of cells (10(6) to 10(10) cells). The basic protocol outlines preparation of purified human T lymphocytes. The method produces good yields of pure T cells prepared by negative selection (i.e., not labeled with antibody). The alternate protocol applies similar principles for purifying CD4(+) T cells, and presents refinements of the basic protocol that minimize cost and improve convenience.

Interleukin 12B gene polymorphism and apparent resistance to hepatitis C virus infection

Cellular immunity with interferon gamma production could have a role in protection from hepatitis C virus (HCV). Interleukin (IL)-12 is a key cytokine in promoting such anti-viral T helper 1 (Th1) responses. We hypothesized that a genetic background able to promote cellular responses may be associated with apparent protection from infection and have investigated the distribution of the functional 1188A/C polymorphism of IL-12B in HCV exposed but uninfected cases. The frequency of the high IL-12-producing C allele was determined by restriction enzyme genotyping in 76 exposed-uninfected individuals and 105 healthy controls. Overall, the C allele was found in 27.6% of exposed-uninfected cases compared with 16.7% of healthy controls [chi(2) = 6.3, P = 0.02, odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.1-3.2]. CC genotype was found in 10.5% of exposed-uninfected cases compared with 0.9% controls (chi(2) = 9.3, P = 0.01, OR = 12, 95% CI = 1.5-100). Individuals at high risk of HCV infection yet who remain uninfected may be resistant in some way to infection. In our cohort of exposed-uninfected cases a genetic background of enhanced IL-12 production was associated with apparent resistance to HCV infection. This lends support to a central role for cellular immune responses in protecting from infection.

The value of serum neopterin, interferon-gamma levels and interleukin-12B polymorphisms in predicting acute renal allograft rejection

Acute rejection remains a poor predictor of graft outcome. In this study, we measured serum levels of interferon (IFN)-gamma and neopterin by enzyme-linked immunosorbent assay and a single nucleotide polymorphism (SNP) within the 3' untranslated region of the interleukin (IL)-12 B gene (1188 A/C) to determine whether either of these factors could predict acute rejection in renal transplantation. Significantly higher early post-transplant neopterin levels (days 5-7; 35.7 versus 19.9 nmol/l) were observed in recipients who subsequently rejected their grafts. Post-transplant neopterin levels showed a strong positive correlation with 1-month creatinine levels (Spearman's correlation 0.62, P < 0.001), suggesting macrophage activation early after transplantation. Pretransplant neopterin and IFN-gamma levels and the IL-12B gene SNP did not predict acute rejection in this small retrospective study. The ability to predict acute rejection non-invasively early after transplantation could lead to individual tailoring of immunosuppressive regimens and perhaps lead eventually to longer graft survival.

Comparison of 4% articaine and 0.5% levobupivacaine/2% lidocaine mixture for sub-Tenon's anaesthesia in phacoemulsification cataract surgery: a randomised controlled trial

BACKGROUND/AIMS

[corrected] The aim of this study was to compare the efficacy and safety of 4% articaine with a mixture containing equal volumes of 2% lidocaine and 0.5% levobupivacaine without hyaluronidase for sub-Tenon's anaesthesia in phacoemulsification cataract surgery.

METHODS

The study was a prospective, randomised double-masked clinical trial of 65 patients allocated to receive either 4% articaine or a mixture containing equal parts of 2% lidocaine and 0.5% levobupivacaine. All patients had pre- and postoperative Hess charting to document ocular motility dysfunction. Ocular and eyelid movements were scored at 2 min intervals from 2 to 10 min after injection of the anaesthetic agent, and at the end of surgery. Complications related to injection, including pain, chemosis and subconjunctival haemorrhage, were recorded. Patients rated pain (none/mild/moderate/severe) during surgery. The operating surgeon masked to the anaesthetic agent assessed proptosis/chemosis at the start of the operation and the degree of ocular akinesia and analgesia at the end of surgery.

RESULTS

The articaine group demonstrated a rapid onset of ocular akinesia with a mean time to readiness for surgery (achieving a score of </=5) of 4.0 min compared with 10 min for the lidocaine/levobupivacaine group (p = 0.001). The effectiveness of block was significantly greater in the articaine group at all points (p<0.01). Surgeons rated ocular akinesia to be superior in the articaine group (p<0.001). Patients and surgeons rated the analgesic effect as comparable in either group. Eyelid scores, subconjunctival haemorrhage and chemosis were comparable in either group. Hess chart was performed on all patients pre- and postoperatively. There was no clinically significant motility disturbance in the articaine group, whereas one patient in the lidocaine/levobupivacaine group developed diplopia with abnormal ocular motility on the Hess chart.

CONCLUSION

Articaine (4%) is a safer and a superior anaesthetic agent than a mixture of 2% lidocaine and 0.5% levobupicaine in achieving ocular akinesia for sub-Tenon's block in phacoemulsification cataract surgery.

Displacement of nuclear fragments into the vitreous complicating phacoemulsification surgery in the UK: incidence and risk factors

AIMS

To study the epidemiology and risk factors contributing to displacement of nuclear fragments into the vitreous (DNFV) complicating phacoemulsification in the UK.

METHODS

Cases were collected prospectively between March 2003 and March 2004 by active surveillance through the British Ophthalmological Surveillance Unit (BOSU). Case-control analysis of risk factors was performed by visiting 10 randomly selected centres using a total of 521 cases of uncomplicated phacoemulsification. Validation analysis to assess under-reporting was performed in a total of 13 randomly selected units.

RESULTS

610 cases of DNFV were confirmed during the reporting period. The estimated incidence of DNFV was 0.19-0.28%. The group with complications was significantly older than the control group (mean 76.8 vs 74.3 years: p<0.001). Significant preoperative risk factors were posterior synechiae (5.1% vs 2.2%), incomplete pupil dilation (59.5% vs 8.8%), pseudoexfoliation (5.6% vs 1.4%) and previous vitrectomy (7.8% vs 2.2%). Significant operative variables related to surgical experience, topical (14.3% vs 3.1%) and sub-Tenon's (51.4% vs 37.2%) anaesthesia, and requirement for vision blue (trypan blue ophthalmic solution) (13.7% vs 2.4%).

CONCLUSIONS

The estimated incidence of DNFV during phacoemulsification surgery in the UK is two or three per 1000 operations. Risk factors have been identified that should help to guide case selection for phacoemulsification surgery and modify techniques.

Plasma levels of endothelin-1 after a pulmonary embolism of bone marrow fat

BACKGROUND

During orthopedic surgery, embolization of bone marrow fat can lead to potentially fatal, intra-operative cardiovascular deterioration. Vasoactive mediators may also be released from the bone marrow and contribute to these changes. Increased plasma levels of endothelin-1 (ET-1) have been observed after pulmonary air and thrombo-embolism. The role of ET-1 in the development of acute cardiovascular deterioration as a result of bone marrow fat embolization during vertebroplasty was therefore investigated.

METHODS

Bone cement was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output, arterial and mixed venous blood gas parameters and plasma ET-1 concentrations were measured at selected time points. Post-mortem, lung biopsies were taken for analysis of intravascular fat.

RESULTS

Cement injections resulted in a sudden (within 1 min) and severe increase in pulmonary arterial pressure (>100%). Plasma concentrations of ET-1 started to increase after the second injection, but no significant changes were observed. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSION

Cement injections into vertebral bodies elicited fat embolism resulting in subsequent cardiovascular changes that were characterized by an increase in pulmonary arterial pressure. Cardiovascular complications as a result of bone marrow fat embolism should thus be considered in patients undergoing vertebroplasty. No significant changes in ET-1 plasma values were observed. Thus, ET-1 did not contribute to the acute cardiovascular changes after fat embolism.

Activation of the novel estrogen receptor G protein-coupled receptor 30 (GPR30) at the plasma membrane

G protein-coupled receptor 30 (GPR30), a seven-transmembrane receptor (7TMR), is associated with rapid estrogen-dependent, G protein signaling and specific estrogen binding. At present, the subcellular site of GPR30 action is unclear. Previous studies using antibodies and fluorochrome-labeled estradiol (E2) have failed to detect GPR30 on the cell surface, suggesting that GPR30 may function uniquely among 7TMRs as an intracellular receptor. Here, we show that detectable expression of GPR30 on the surface of transfected HEK-293 cells can be selected by fluorescence-activated cell sorting. Expression of GPR30 on the cell surface was confirmed by confocal microscopy using the lectin concanavalin A as a plasma membrane marker. Stimulation of GPR30-expressing HEK-293 cells with 17beta-E2 caused sequestration of GPR30 from the cell surface and resulted in its codistribution with clathrin and mobilization of intracellular calcium stores. Evidence that GPR30 signals from the cell surface was obtained from experiments demonstrating that the cell-impermeable E2-protein conjugates E2-BSA and E2-horseradish peroxidase promote GPR30-dependent elevation of intracellular cAMP concentrations. Subcellular fractionation studies further support the plasma membrane as a site of GPR30 action with specific [3H]17beta-E2 binding and G protein activation associated with plasma membrane but not microsomal, or other fractions, prepared from HEK-293 or SKBR3 breast cancer cells. These results suggest that GPR30, like other 7TMRs, functions as a plasma membrane receptor.

Effect of pupillary dilatation on glaucoma assessments using optical coherence tomography

AIMS

To examine the effect of pupillary dilatation on the reliability of retinal nerve fibre layer (RNFL) and optic nerve head (ONH) assessments using Stratus OCT in a glaucoma clinic.

METHODS

Observational study of 38 patients attending a glaucoma clinic. The "fast optic disc" and "fast RNFL thickness" programs on Stratus OCT were used to measure the RNFL thickness and ONH cup to disc ratio (CDR). Two scans were done before dilatation and two after dilatation with tropicamide 1% drops. The mean values and reproducibility before and after dilatation were compared, along with the quality of scans as indicated by the "signal strength" score.

RESULTS

In nine patients (23.7%) no images were obtained undilated but after dilatation examination was possible in all patients. Inability to obtain an undilated scan was associated with smaller pupil size and increasing cataract. The scan quality, as judged by the signal strength score, was higher dilated than undilated for both RNFL thickness (p = 0.011) and ONH CDR (p = 0.007). Reproducibility was higher with dilated scans for RNFL thickness but not for ONH CDR. There were significant differences between the dilated and undilated examinations for three of the five RNFL thickness variables and two of the three ONH CDR categories.

CONCLUSIONS

Acquisition of high quality OCT images was not possible without pupillary dilatation in about 25% of the patients. The dilated scans were more reproducible and of higher quality than the undilated scans. The two methods of examination do not appear to be interchangeable, suggesting that in follow up examinations the pupil should be in the same condition as at baseline. Pupillary dilatation is recommended before glaucoma assessments using Stratus OCT.

Long term clinical outcome and bleeding complications among hospital survivors with acute coronary syndromes

OBJECTIVE

To examine the 21 month clinical outcome and bleeding complications in hospital survivors with non-ST segment elevation acute coronary syndromes (NSTEACS) who were discharged with combined clopidogrel and aspirin anti-thrombotic therapy, and compare with those having ST segment elevation myocardial infarction (STEMI) who were discharged with aspirin alone.

DESIGN

Observational study.

SETTING

A large university hospital.

PATIENTS

224 patients were admitted to hospital with either NSTEACS or STEMI, and survived to discharge between 1 October 2001 and 31 December 2002.

MAIN OUTCOME MEASURES

Cardiovascular death, total death, new myocardial infarction, unstable angina requiring hospitalisation, stroke or transient ischaemic attack, coronary revascularisation; and fatal, life threatening, major and minor bleeding over 21 months after discharge.

RESULTS

Despite having no or small infarct (median maximum creatine kinase 155 v 1295 u/l; p<0.001) and taking more antianginal drugs, patients with NSTEACS had similar rates of cardiovascular death (9.5% v 8.3%; p = NS), new myocardial infarction (9.5% v 6.5%; p = NS) or unstable angina requiring hospitalisation (15.5% v 10.2%; p = NS) when compared with STEMI. Fatal, life threatening or major bleeding were <1% in both groups (p = NS); and minor bleeding occurred in 4.3% NSTEACS and 2.8% STEMI patients respectively (p = NS).

CONCLUSIONS

Patients with NSTEACS had a similar and unfavourable long term outcome when compared with STEMI. There was no difference in serious bleeding complications between both groups.

Review article: scoring systems for assessing prognosis in critically ill adult cirrhotics

BACKGROUND

Cirrhotic patients admitted to intensive care units (ICU) still have poor outcomes. Some current ICU prognostic models [Acute Physiology and Chronic Health Evaluation (APACHE), Organ System Failure (OSF) and Sequential Organ Failure Assessment (SOFA)] were used to stratify cirrhotics into risk categories, but few cirrhotics were included in the original model development. Liver-specific scores [Child-Turcotte-Pugh (CTP) and model for end-stage liver disease (MELD)] could be useful in this setting.

AIM

To evaluate whether ICU prognostic models perform better compared with liver-disease specific ones in cirrhotics admitted to ICU.

METHODS

We performed a structured literature review identifying clinical studies focusing on prognosis and risk factors for mortality in adult cirrhotics admitted to ICU.

RESULTS

We found 21 studies (five solely dealing with gastrointestinal bleeding) published during the last 20 years (54-420 patients in each). APACHE II and III, SOFA and OSF had better discrimination for correctly predicting death compared with the CTP score. The MELD score was evaluated only in one study and had good predictive accuracy [receiver operator characteristic (ROC) curve: 0.81). Organ dysfunction models (OSF, SOFA) were superior compared with APACHE II and III (ROC curve: range 0.83-0.94 vs. 0.66-0.88 respectively). Cardiovascular, liver and renal system dysfunction were more frequently independently associated with mortality.

CONCLUSIONS

General-ICU models had better performance in cirrhotic populations compared with CTP score; OSF and SOFA had the best predictive ability. Further prospective and validation studies are needed.

Photopatch testing of 1155 patients: results of the U.K. multicentre photopatch study group

BACKGROUND

Photoallergic contact dermatitis can be difficult to diagnose if not appropriately investigated. Currently, the most common U.K. photoallergens appear to be sunscreen chemicals. The investigation of choice is photopatch testing (PPT), which is probably underused. In part, this is due to differences in methodology and results interpretation.

OBJECTIVES

To conduct PPT using a group of sunscreen chemicals, defined indications and a standardized methodology including interpretation and relevance of reactions in patients attending for investigation at 17 centres across the U.K., Ireland and the Netherlands.

METHODS

Patients (n = 1155) who fulfilled the inclusion criteria were investigated with PPT using sunscreen chemicals in addition to suspected topical products. Readings were taken at 24, 48 and 72 h following standardized ultraviolet A irradiation (5 J cm(-2)). The clinical relevance of any reaction was recorded.

RESULTS

Of the 1155, 130 had allergic reactions (11.3%). Of these, 51 had photoallergy (PA) (4.4%), 64 had contact allergy (CA) (5.5%), and 15 patients had combined PA and CA (1.3%). Multiple PA was seen in some. The most common photoallergen was benzophenone-3 (27 reactions; 21%). Most reactions (60%) were clinically relevant. The most common indication for testing in patients found to have PA was a history of reacting to a sunscreen (41%). The other 59% had an exposed-site dermatitis/skin problem or a photodermatosis. Some centres (n = 8) performed readings after the standard 48-h reading, and an extra 32 PA and 22 CA reactions were detected, which were not evident at 48 h. A new photoallergen (octyl triazone) was detected in two patients.

CONCLUSIONS

Sunscreen PA and CA are probably equally uncommon. Most reactions, of both reaction types, were relevant clinically. A large proportion of patients (59%) found to have PA was unaware of reacting to a sunscreen chemical, suggesting that PA should be considered as an explanation in any exposed-site dermatitis. Although this study focused on reactions at 48 h postirradiation, readings performed up to 96 h, while inconvenient, add value by detecting additional relevant responses. A previously unknown photoallergen was found, highlighting the need for awareness of novel photoallergens in the marketplace. A standardized PPT method not only encourages more use of this investigation, but also facilitates comparison of results between centres and so will improve our understanding of PA.

Neurosurgical trainees operative experience before and after introduction of the New Deal for junior doctors

To compare operative experience before and after implementation of the New Deal to reduce junior doctors working hours, operative data was audited over a 6-month period. The three registrars with national training numbers in our unit were placed on two virtual working patterns to determine what their operative experience would have been over that 6-month period. Comparison with a 1980s trainee over a similar period was also made. Trainees on a 1:3 rota would have performed more emergency operations [32 (28 - 38)], than those on a partial shift [1:6 with following day off, 16 (13 - 23)]. Particular examples include trauma craniotomies 13 (9 - 15) versus 6 (3 - 11) and CSF diversion, 9 (2 - 13) versus 4 (2 - 7). Although trainees on a 1:3 on call rota would have had more emergency operative experience over the same period of time, less common procedures, such as lumber decompression for cauda equina syndrome, were equally distributed between both groups. Trainees doing the partial shift would have lost 18 (12 - 24) elective cases over the same period as a result of enforced absence following periods of duty. These included posterior fossa, complex spinal, benign and rare cranial procedures. The increasingly common option of employing juniors on a full shift rota would have an even greater impact on training. Trainees are unavailable for elective training on night shift and then for a compensatory period afterwards, doubling the time spent away from formal surgical training. Indiscriminate reduction in working hours by enforced absence for compensatory rest has a potentially deleterious impact on elective training. By reducing the out of hours commitment trainees have a reduced, but possibly acceptable, exposure to emergency neurosurgery without impact on elective training.

Risk factors, sequential organ failure assessment and model for end-stage liver disease scores for predicting short term mortality in cirrhotic patients admitted to intensive care unit

BACKGROUND

Prognostic scores in an intensive care unit (ICU) evaluate outcomes, but derive from cohorts containing few cirrhotic patients.

AIMS

To evaluate 6-week mortality in cirrhotic patients admitted to an ICU, and to compare general and liver-specific prognostic scores.

METHODS

A total of 312 consecutive cirrhotic patients (65% alcoholic; mean age 49.6 years). Multivariable logistic regression to evaluate admission factors associated with survival. Child-Pugh, Model for End-stage Liver Disease (MELD), Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores were compared by receiver operating characteristic curves.

RESULTS

Major indication for admission was respiratory failure (35.6%). Median (range) Child-Pugh, APACHE II, MELD and SOFA scores were 11 (5-15), 18 (0-44), 24 (6-40) and 11 (0-21), respectively; 65% (n = 203) died. Survival improved over time (P = 0.005). Multivariate model factors: more organs failing (FOS) (<3 = 49.5%, > or =3 = 90%), higher FiO(2), lactate, urea and bilirubin; resulting in good discrimination [area under receiver operating characteristic curve (AUC) = 0.83], similar to SOFA and MELD (AUC = 0.83 and 0.81, respectively) and superior to APACHE II and Child-Pugh (AUC = 0.78 and 0.72, respectively).

CONCLUSIONS

Cirrhotics admitted to ICU with > or =3 failing organ systems have 90% mortality. The Royal Free model discriminated well and contained key variables of organ function. SOFA and MELD were better predictors than APACHE II or Child-Pugh scores.

Classifying Antibodies Using Flow Cytometry Data: Class Prediction and Class Discovery

Classifying monoclonal antibodies, based on the similarity of their binding to the proteins (antigens) on the surface of blood cells, is essential for progress in immunology, hematology and clinical medicine. The collaborative efforts of researchers from many countries have led to the classification of thousands of antibodies into 247 clusters of differentiation (CD). Classification is based on flow cytometry and biochemical data. In preliminary classifications of antibodies based on flow cytometry data, the object requiring classification (an antibody) is described by a set of random samples from unknown densities of fluorescence intensity. An individual sample is collected in the experiment, where a population of cells of a certain type is stained by the identical fluorescently marked replicates of the antibody of interest. Samples are collected for multiple cell types. The classification problems of interest include identifying new CDs (class discovery or unsupervised learning) and assigning new antibodies to the known CD clusters (class prediction or supervised learning). These problems have attracted limited attention from statisticians. We recommend a novel approach to the classification process in which a computer algorithm suggests to the analyst the subset of the "most appropriate" classifications of an antibody in class prediction problems or the "most similar" pairs/ groups of antibodies in class discovery problems. The suggested algorithm speeds up the analysis of a flow cytometry data by a factor 10-20. This allows the analyst to focus on the interpretation of the automatically suggested preliminary classification solutions and on planning the subsequent biochemical experiments.

Detecting antibodies with similar reactivity patterns in the HLDA8 blind panel of flow cytometry data

The blind panel collected for the 8th Human Leucocyte Differentiation Antigens Workshop (HLDA8; ) included 49 antibodies of known CD specificities and 76 antibodies of unknown specificity. We have identified groups of antibodies showing similar patterns of reactivity that need to be investigated by biochemical methods to evaluate whether the antibodies within these groups are reacting with the same molecule. Our approach to data analysis was based on the work of Salganik et al. (in press) [Salganik, M.P., Milford E.L., Hardie D.L., Shaw, S., Wand, M.P., in press. Classifying antibodies using flow cytometry data: class prediction and class discovery. Biometrical Journal].

The effects of isotonic and isokinetic muscle stretch on the excitability of the spinal alpha motor neurones in patients with muscle spasticity

To examine the effect of isotonic (with and without weight bearing) and isokinetic muscle stretch on the excitability of the spinal alpha motor neurones (alphaMN) in patients with spasticity and to establish whether this effect is maintained for at least 24 h after the intervention. A single 20-min session of isotonic muscle stretch (with or without weight bearing) or isokinetic stretch was delivered to the ankle plantar flexors in patients with post-stroke lower limb spasticity and healthy control subjects. The effect of these types of muscle stretch on the excitability of alphaMN was assessed by measuring the latency of the Hoffmann reflex (H-reflex) and the ratio of the amplitude of the maximum H-reflex (H(max)) to that of the maximum action motor potential of the soleus muscle (M(max)). Sixty-six hemiplegic stroke patients and 21 healthy control subjects were recruited and completed the trial. The H(max):M(max) ratio was significantly higher in patients with spasticity than in healthy control subjects. However, there were no statistically significant differences in the H-reflex latency or the change in H(max):M(max) ratio between the baseline values and those recorded immediately after the therapy intervention or 24 h later for each type of muscle stretch. Similarly, there were no significant differences in these variables between the interventions. In the present study neither isotonic muscle stretch (with or without weight bearing) or isokinetic stretch had a statistically significant effect on the excitability of the alphaMN in patients with muscle spasticity. This suggests that the previously reported reduction in spasticity after muscle stretch is because of mechanisms other than the direct effect on alphaMN. However, the lack of a demonstrable benefit of treatment may be due the fact that we examined the effects of a single, rather than repeated treatment cycles.

Under-use of beta-blockers in patients with ischaemic heart disease and concomitant chronic obstructive pulmonary disease

BACKGROUND

Beta-blockers (BB) improve morbidity and mortality in ischaemic heart disease. There is a general reluctance to use BB, especially in patients with chronic obstructive pulmonary disease (COPD), which is perceived as an absolute contraindication. As large numbers of patients are labelled with COPD without objective evidence, they may miss out on the benefit from these drugs.

AIM

To assess the use of BB in patients with COPD admitted with acute coronary syndrome (ACS), and to assess the supporting evidence for the diagnosis of COPD in these patients.

METHOD

Case-note review and retrospective analysis of 457 consecutive patients admitted with troponin-positive ACS between October 2002 and October 2003.

RESULTS

Of 457 ACS patients studied, 246 (54%) were discharged on a BB. Cardiologists prescribed BB in ACS patients more frequently than did general physicians, (70% vs. 30%, respectively). The reasons for withholding BB were: not documented 27%, COPD 33%, heart failure 24%, others 16%. Ninety-four patients (21%) had a diagnosis of COPD; only 58 (62%) of these had been reviewed by a chest physician or had previous pulmonary function tests. Of the 94 patients with COPD, only 15 (16%) were prescribed BB during the admission: 9 by cardiologists and 6 by non-cardiologists. BB were discontinued in two patients due to an increase in dyspnoea.

CONCLUSION

Many patients with a diagnosis of COPD have no objective evidence to support the diagnosis and are denied the prognostic benefits of BB when presenting with ACS. Before withholding beta-blockers, COPD and reversibility should be ascertained by pulmonary function testing. The overall use of beta-blockers remains sub-optimal and could be improved in this setting.

The geographical distribution of specialists in public health in the United Kingdom: is capacity related to need?

OBJECTIVES

Recent organizational changes reflect the need to be more responsive to local populations and have included fostering a closer structural relationship between primary care and public health. In light of this, we explore the distribution of the specialist public health workforce and the relationship with population deprivation and need.

STUDY DESIGN

Questionnaire survey to all directors of public health working in primary care trusts (PCTs) and strategic health authorities (SHAs) in England to determine the number of specialists in public health working in either PCTs or SHAs. All identified specialists were given the opportunity to self-define in a further questionnaire survey. Whole-time-equivalent staffing, per head of population, was analysed against socio-economic deprivation, measured by the DETR 2000 Index of Multiple Deprivation. The analysis was conducted at the SHA level.

RESULTS

The survey was undertaken whilst public health in the UK was undergoing immense change. This presented specific challenges in identifying specialists in public health working within PCTs and SHAs. Seven hundred and eighty-three specialists working in PCTs and SHAs were identified. On average, in England, there are 1.69 specialists in public health per 100,000 population, with some variability at SHA level (range = 0.8-2.89). Findings indicate an overall positive association between capacity at SHA level and socio-economic need, although some discrepancies between need and provision are apparent.

CONCLUSIONS

The general positive association between capacity and deprivation should offer some reassurance to policy makers, researchers and patients alike. However, further efforts are needed to redistribute specialists in some areas to address organizational capacity and equity issues.

Purine modulation of cytokine release during diuretic therapy of rheumatoid arthritis

Since free radicals are implicated in rheumatoid arthritis (RA) and since uric acid is a free radical scavenger, we examined the effects of treating RA patients with with the diuretic bumetanide to try to improve their arthritic control. Seventy patients, aged 18-75 years, were randomised to receive bumetanide 4 mg/day or placebo. Uric acid levels increased, but not that of other purines, in the blood of drug-treated patients compared with placebo-treated controls. There were no significant changes in clinical measurements of disease activity or in ESR or CRP levels. There were no over all differences in the blood levels of the cytokines, nor in the basal or stimulated production of cytokines from the blood cultures. The adenosine receptor agonist 5'N-ethylcarboxamido-adenosine (NECA) used to modify cytokine release in cultures of whole blood taken from the patients, depressed the release of tumour necrosis factor-alpha (TNFalpha), but failed to depress the release of interleukin-1b (IL-1b) or interleukin-6 (IL-6), a difference from earlier studies of healthy control subjects and, thus, a difference which may contribute to the disease activity.